Field of the Invention
The present invention relates to a method for the colorimetric detection of at least one analyte in a sample, preferably multiple analytes in a sample, and membranes for use in the method.
Background Information
Biomarkers can identify disease prior to exhibition of clinical symptoms by a subject, and therefore provide the ability to treat the molecular basis of disease using targeted therapies. Thus, biomarkers allow the pharmacodynamic effects of targeted therapeutics to be evaluated before clinical signs and symptoms become evident.
New biomarkers are being discovered by means of a large number of proteomic and genomic studies using low throughput, labour intensive technologies such as mass spectrometry and high performance liquid chromatography. These technologies are great discovery tools for identifying novel biomarkers in small numbers of samples from subjects. However, biomarkers must be qualified by testing large numbers of samples from subjects before being accepted as a clinically valid biomarker. Currently available technologies for screening large numbers of samples from subjects are expensive and cumbersome.
Colorimetric immunoassays are often considered the accepted standard for single protein measurement. These assays typically involve a primary antigen-specific antibody to bind the target antigen from the sample, with antigen binding detected using a secondary antibody linked to a colorimetric detection system. The most widely used format is enzyme-linked immunosorbent assays (ELISA), having well-established protocols for the measurement of single proteins in solutions.
There is a need for simple, rapid and cost-effective diagnostic tests that can be used to detect biomarkers in biological samples. The increasing interest in the simultaneous measurement of multiple proteins in samples has lead to the development of multiplexed immunoassays in a microarray format. Protein-based microarrays are currently used for a variety of applications. However, this technology has yet to be adopted as a routine method for diagnostic testing, due to technical challenges surrounding the sensitivity, specificity and cross-reactivity of the assay reagents and the need for expensive instrumentation. Accordingly, technologies are needed that can rapidly develop and implement assay methods adapted for high throughput, scalable and cost-effective screening to validate the utility of biomarkers across large segments of the population.